This invention relates to woodburning heating apparatus and more particularly to such apparatus having high heating efficiency and generating low levels of polluting emissions.
As wood burns in a modern, airtight woodburning stove, products of combustion are created containing polluting emissions including particulate material which is discharged into the atmosphere and compounds such as creosote which can condense onto the inside surface of the chimney. Creosote build-up is dangerous in that it can ignite causing a hazardous chimney fire. Other emissions are damaging to the environment. Furthermore, exhaust gases contain substantial quantities of unburned material whose heating value is thus wasted as they are discharged into the atmosphere.
It is known to pass combustion gases from a woodburning stove through catalytic converters to improve heating efficiency and reduce harmful emissions. The known systems generally dispose the converter within the stove pipe outside the body of the heating apparatus or in the top of the apparatus near the stovepipe connection. Catalytic converters usually consist of a perforate honeycomb structure of ceramic or other material coated with a catalyst material such as platinum, palladium or rhodium. The surface properties of these materials are such that combustion products, too cool to burn on their own, will ignite within the catalytic converting apparatus.
It is also known to retrofit catalytic converting apparatus within conventional woodburning stoves. The potential efficiencies to be gained from catalytic converters, however, have not been achieved in the retrofit stoves because they have not been designed from the beginning to make the best use of catalytic converter apparatus.
It is therefore an object of this invention to provide woodburning heating apparatus which takes full advantage of the catalytic conversion or igniting apparatus.
Another object of the invention is woodburning heating apparatus which is highly efficient in delivering heat into a room to be heated.
Yet another object of this invention is woodburning heating apparatus which substantially reduces the level of harmful emissions into the atmosphere.
A still further object of this invention is woodburning heating apparatus which reduces the build-up of creosote in a chimney.